Gage pressure transducers are often used to measure gage/differential pressures in harsh environments. Generally, gage pressure transducers comprise two pressure sensing assemblies, with one pressure sensing assembly being exposed to a main pressure and the other being exposed to a reference pressure. Each pressure sensing assembly includes a half-bridge sensor such that when they combine together, they provide a gage pressure measurement of the environment to be measured.
Many of the gage pressure transducer assemblies of the prior art, however, present shortcomings that interfere with the accuracy of the gage pressure measurement. For example, some embodiments utilize non-oil filled pressure capsules contained in a non-hermetic gage transducer assembly. The non-hermeticity of this gage transducer assembly enables the harsh environment to interfere with the operation of the transducer assembly, which consequently may adversely affect the accuracy of overall gage pressure measurement. In another example, other embodiments utilize wire-bonded oil filled pressure capsules, which require large volumes of oil to operate. Large volumes of oil, however, cause significant back pressure against the deflecting diaphragm, which also interferes with the accuracy of the overall gage pressure measurement.
Accordingly, there is a need for a gage pressure transducer assembly that utilizes hermetically sealed pressures sensing assemblies such that harsh environments do not interfere with the operation and, further, an assembly that utilizes minimal oil, such that back pressures associated with large oil volumes can be reduced.